Electrolyte and battery comprising same

Abstract

The invention discloses an electrolyte and a battery comprising the electrolyte. The electrolyte comprises an additive A and an additive B, the additive A is at least one of 2-ethynyl-1, 3-dioxocyclopentane compounds, and the additive B is at least one of sulfate compounds. According to the electrolyte disclosed by the invention, through mutual cooperation of the additive A and the additive B, not only is the acidity of the electrolyte prevented from being increased, but also an oxidation-resistant interface protection film is formed on the surface of a positive electrode, and an SEI film with relatively low impedance is formed on the surface of a negative electrode, so that the fast-charge cycle performance of the battery is improved; and the electrolyte provided by the invention has relatively good stability in long-term circulation. When the non-aqueous electrolyte is applied to a battery, the non-aqueous electrolyte has relatively good quick-charge cycle performance, long-term high-temperature cycle performance, long-term high-temperature storage performance and relatively low volume expansion rate.

Description

technical field [0001] The invention belongs to the field of battery materials, and in particular relates to an electrolyte and a battery comprising the electrolyte. Background technique [0002] Ternary layered oxides have excellent comprehensive properties such as high energy density, good cycle performance, and moderate price, and are currently the most promising type of cathode materials in lithium-ion batteries (LIBs). With the rapid development of pure electric vehicles (EVs) and hybrid electric vehicles (HEVs), the requirements for the energy density, cycle life and safety performance of LIBs are constantly increasing. However, in traditional electrolyte systems, ternary cathode materials will undergo drastic structural changes and interfacial side reactions at high voltage and high temperature, which poses great challenges to practical applications, especially for LIBs using high-nickel ternary materials. Cycle life and safety present great challenges. At present, ...

AI Technical Summary

Problems solved by technology

Among them, the problems of the material itself include: first, the mixed discharge of Ni / Li during the cycle, resulting in a phase transition reaction, which in turn induces the stress-strain effect, resulting in capacity decay during the cycle of the material; 4+ tends to reduce to Ni 3+ , so that oxygen is released from the material, and the thermal stability of the material deteriorates

The large amount of interface refers to the instability of the electrode / electrolyte interface in the actual electrochemical environment, which is easily corroded by free acid in the electrolyte, resulting in low battery capacity retention and poor high temperature performance.

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